At the time of Guru Nanak, Punjab had no set language. There were different dialects and scripts, e.g. Sharda Takri (Thakri), Persian and Bhatt Akhri, etc. The 52-letter script was a mixture of several languages.

Guru Nanak Dev ji observed that there were many superfluous letters in that script so he composed Patti, which depicted only 35 letters. He even gave the pronunciation of each letter. He asked Bhai Lehna (Guru Angad Dev Ji) to put all the letters in an alphabet form and in a proper order. Bhai Lehna who was a scholar, and poet, and was also fully conversant with all these scripts readily agreed to accomplish the task. He prepared the alphabet and put the same to his Master who gave his approval. As Bhai Lehna devised the script, the same is known as Gurmukhi - a language devised by a Gurmukh at the instance of the Guru. This script was adopted by all the composers of Bani and in the same very script was written Aad Sri Guru Granth Sahib. The language enshrined in this script came to be known as Punjabi and is being treated as the language of Punjab. With the passage of time it has spread to all the corners of the world and is universally acclaimed as a very rich and developed language.